D6 FieldInstancePerViewMode has a default viewmode with no settings

Looks good, but let's see a test triggering the notice.

I've added a (rather convoluted) test to trigger the notice, but I'm not familiar enough with D6 to know how this situation could occur.

@joelpittet's solution would not solve this particular problem so I have added an attempt of my own. The notice occurs when $field_row['display_settings']['label'] is not set, checking !empty($field_row['display_settings'][$view_mode]) will not confirm this.

I would be interested in your feedback on my interpretation.

+++ b/core/modules/field/src/Plugin/migrate/source/d6/FieldInstancePerViewMode.php
@@ -37,7 +37,13 @@ protected function initializeIterator() {
+            $label = 'hidden';

I checked to see if we had a constant for this value. We don't - see \Drupal\Core\Entity\EntityDisplayBase

+++ b/core/modules/field/src/Plugin/migrate/source/d6/FieldInstancePerViewMode.php
@@ -37,7 +37,13 @@ protected function initializeIterator() {
+          if (!empty($field_row['display_settings']['label']['format'])) {
+            $label = $field_row['display_settings']['label']['format'];
+          }
+          else {
+            $label = 'hidden';
+          }

I guess one question here is should we put this logic here or should it go into the migration using \Drupal\migrate\Plugin\migrate\process\DefaultValue?

@alexpott I think it simplest to leave it here because display_settings needs unserialising before checking whether ['label']['format'] is not empty (and I for one don't know whether that's even possible without a custom process plugin).

What type of field causes the view mode to have no settings? I was unable to reproduce it on a D6 site. At least, lets add a comment.

Since this is just setting a value for label why can't we add a default value in the pipeline at "options/label": label ?

Could we get steps to reproduce here?

Thanks.

If steps are available to reproduce this, please reopen.